Previous results on stability of \(T\)  were established in
[1]}.
If \(h\)  denotes the genus of \(Z \rightarrow B\) , they proved the
restriction of \(T\)  to a general fiber of \(Y \rightarrow B\)  is
semistable whenever \(h \ge dg + d(d-1)^2 g\) 
[1]}.

